Cleaver-Brooks CBH 40 - Page 37

The timer resumes operation. When the dial indi-
cator reaches the start or dot position the timer
and blower motor will be de-energized. The lock-
out switch must be manually re-set before opera-
tion can be resumed. (Refer to caution above.)
18. Pilot but no main flame.
If the pilot flame is proven, the main fuel valve cir-
cuit is energized from terminal 7. The pilot flame
will be extinguished 10 seconds later. The flame
detecting circuit will break within 4 seconds to
drop out the flame relay 2K. The main fuel valve
circuit is de-energized to stop the flow of fuel. The
blower motor continues to run.
The lockout switch will trip approximately 30
seconds later and relay lK will be de-energized.
The flame failure light and alarm bell (optional)
are energized.
The timer resumes operation. When the dial indi-
cator reaches the start or dot position the timer
and blower motor will be de-energized. The lock-
out switch must be manually reset before operation
can be resumed. (Refer to caution above.)
C. Loss of flame.
If a flame outage occurs during normal operation
and/or the flame is no longer sensed by the de-
tector, the flame relay 2K will trip within 4 se-
conds to de-energize the fuel valve circuit and shut
off fuel flow. The blower motor continues opera-
tion. Approximately 30 seconds later the lockout
switch will trip to de-energize master relay lK.
The flame failure light and alarm bell (optional)
are energized.
The timer resumes operation. When the dial indi-
cator reaches the start or dot position the timer
and blower motor will be de-energized. The lock-
out switch must be manually reset before operation
can be resumed. (Refer to caution above.)
If the burner will not start, or upon a safety lock-
out, the trouble shooting section in the operating
manual and the technical bulletin should be re-
ferred to for assistance in pinpointing problems
that may not be readily apparent. Familiarity with
the programmer and other controls in the system
can be obtained by studying the contents of the
manual and this bulletin. Knowledge of the system
and its controls will make troubleshooting much
easier in the event it is necessary. Costly down time
or delays can be prevented by systematic checks of
the actual operation against the normal sequence
to determine the stage at which performance de-
viates from normaL Following a routine may pos-
sibly eliminate overlooking an obvious condition,
often one that is relatively simple to correct.
Remember that this is a safety device and for the
most part it is doing its job when it shuts down or
refuses to operate. Never attempt to circumvent
any of the safety features.
Chapter 3-Sequence of Operation
Preventive maintenance and scheduled inspection
of all components should be followed. Periodic
checking of the relay to see that a safety lockout
will occur under conditions of failure to ignite
either pilot or main flame, or from loss of flame is
recommended.
AB ALARM BELL
AS-I, 2 AUXILIARY SWITCH-I, 2
ALWCO AUXILIARY LOW WATER CUT-OFF
AR ALARM RELAY
BM
BLOWER MOTOR
BMF BLOWER MOTOR FUSES
BMS BLOWER MOTOR STARTER
BMSI BLOWER MOTOR STARTER INTERLOCK
BS BURNER SWITCH
CAPS COMBUSTION AIR PROVING SWITCH
CCF-P CONTROL CIRCUIT FUSE-PRIMARY
CCT CONTROL CIRCUIT TRANSFORMER
CR-I CONTfWL RELAY-I
DISC DISCONNECT
DM DAMPER MOTOR
DMT DAMPER MOTOR TRANSFORMER
DNS DAY-NIGHT SWITCH
DPS DAMPER POSITIONING SWITCH
FD FLAME DETECTOR
FFL FLAME FAILURE LIGHT
FVL FUEL VALVE LIGHT
GOS GAS-OIL SWITCH
GPV GAS PILOT VALVE
HFS HIGH FIRE SWITCH
HFOV-I, 2 HIGH FIRE OIL VALVE-I, 2
HLC
HIGH LIMIT CONTROL
HLFC HIGH-LOW FIRE CONTROL
HGPS HIGH GAS PRESSURE SWITCH
IT IGNITION TRANSFORMER
LOPS LOW OIL PRESSURE SWITCH
LDL LOAD DEMAND LIGHT
LFOV LOW FIRE OIL VALVE
LFS LOW FIRE SWITCH
LWCO
LWL
LGPS
LOW WATER CUT-OFF
LOW WATER LIGHT
LOW GAS PRESSURE SWITCH
MAIN GAS VALVE MGV
MGVAS
MGVV
MAIN GAS VALVE AUXILIARY SWITCH
MAIN GAS V:ENT VALVE
OLC
OL'S
osov
PT
OPERATING LIMIT CONTROL
OVER LOADS
OIL SHUT-OFF VALVE
PURGE TIMER
FIGURE 3-3.
MNEMONIC DESIGNATION OF
ELECTRICAL DEVICES
3-7